Electromagnetic suspended speaker

ABSTRACT

In a preferred embodiment, an electromagnetic audio speaker device including an electromagnetic vibrator connected functionally to a speaker cone, the vibrator and cone being suspended within an inner enclosure having a first speaker opening circumscribing a membrane means attached at the first inner opening periphery and attached to an outer periphery of the cone, the inner enclosure being encased within and spaced from an outer enclosure having a second speaker opening aligned with the first speaker opening, the inner and outer enclosures at their opening peripheries being joined to the outer periphery of the membrane means, the membrane means being an elastomer foam encased between two taut polyethylene membranes, the enclosures each being of plastic sheet material laminated to fiber-board sheet material.

United States Patent [191 Dunning Sept. 11, 1973 [76] lnventor: WilliamS. Dunning, 72-89 Yellowstone Blvd., Forest Hills, N.Y. 11375 221 Filed:Feb. 14,1972

211 Appl. No.2 225,797

Primary Examiner-Stephen}. Tomsky Attorney-William T. l-lough and L aforest S. Saulsbury 57 ABSTRACT In a preferred embodiment, anelectromagnetic audio speaker device including an electromagneticvibrator connected functionally to a speaker cone, the vibrator and conebeing suspended within an inner enclosure having a first speaker openingcircumscribing a membrane means attached at the first inner openingperiphery and attached to an outer periphery of the cone, the innerenclosure being encased within and spaced from an outer enclosure havinga second speaker opening aligned with the first speaker opening, theinner and outer enclosures at their opening peripheries being joined tothe outer periphery of the membrane means, the membrane means being anelastomer foam encased between two taut polyethylene membranes, theenclosures each being of plastic sheet material laminated to fiber-boardsheet material.

1 12 Claims, 3 Drawing Figures 1 ELECTROMAGNETIC SUSPENDED SPEAKERBACKGROUND TO THE INVENTION Prior to the present invention, theApplicants own abovenoted patents represent the sole relevant prior artexisting over which the present invention is in particular animprovement, except that for all types of existing speakers it isdesirable to improve the quality of reproduction especially of each ofhigh and low frequency sounds which rarely are reproduceable by a singlespeaker with any reasonable degree of accuracy and quality. It should beadditionally noted however that US. Pat. No. 3,424,873 discloses anembodiment having a liquid encompassed between two loosely supportingmembranes; the rigid support of the electromagnet end of the cone, andthe loose state of support of the wide end of the cone as well as theemployment of vibration transmitting liquid each serves to defeat one ormore objects of the present invention described hereafter.

SUMMARY OF THE INVENTION Accordingly it is an object of the presentinvention to obtain a speaker unit solving the above-type problems anddifficulties.

Another object of the present invention is to eliminate structure offormer cabinets not necessary when the present invention is utilized.

Another object is to further improve sound quality and reduceinterferences such as resonance by preferred cabinet structure andcomposition together with improvements noted in the preceding objects.

Other objects become apparent from the preceding and followingdisclosure.

One or more of the preceding objects are obtained by the invention asdefined hereafter.

The invention broadly encompasses an electromagnetic speaker includingthe cone and electromagnet mounted for support thereof on a suspendingmembrane unit attached supportingly at the outer perimeter of the cone,with the membrane unit being mounted at its outer extremities at theperiphery of a double-walled enclosing structure enclosing the cone, thedoublewalled structure defining the space between the two walls and eachof the enclosures of the double-walled structure having commonly alignedspeaker-mounting openings across which the supporting membrane unit issuspended in a taut state. The major improvement of the present speakersystem resides in the combination as described above, with the membraneunit being composed of a plurality of membranes each having oppositefaces with an intermediate media between opposing faces of theplurality, typically there being two stretched-taut membranes ofpolyester having typically polyurethane foam encased firmly between thetaut membranes preferably along the entire opposing faces of themembranes. However, it is within the scope of the invention to use anyelastomeric material as the intermediate media, including not only foamsand including not only typical elastomers but additionally encompassingthe possible use of any material capable of cushioning the sandwichingmembranes, such as encapsulated rubber, another polyester sheet, powder,or any other such suitable material.

The enclosure structures preferably are of laminated plastic sheet andcellulosic fiber-board sheets whereby resonance disturbances atdifi'erent sound frequencies are substantially eliminated as a result ofthe plastic and the fiber-board having resonance at differentfrequencies which resonances are further reduced by virtue of thelamination of one to the other.

THE FIGURES FIG. 1 illustrates a perspective view of a loudspeakerassembly embodying the invention.

FIG. 2 illustrates a vertical enlarged central sectional view takenalong lines 2-2 of FIG. 1.

FIG. 3 illustrates an enlarged in-part section as taken within thebroken-lines of FIG. 2, disclosing in particular an embodiment in whichan intermediate media is sandwiched between opposing faces of twomembranous diaphragms, as well as in detail illustrating the mechanismof attachment of the inner and outer enclosures relative to the membraneunit and the cone structure supported by the membrane unit.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates the speakerassembly 5 including the outer enclosure structure 6, the exposed face7a of the membrane unit 7, the securing annular washer (or disk) 8aanchoring the inner edge of the membrane unit to the cone 9 by anchorscrews 10, and outer anchor structure 8b with anchor screws 80. Alsoviewable in part is the speaker electric cord 14.

FIG. 2 further illustrates the cabinet of FIG. 1 as a typical embodimentas taken along lines 2-2 of FIG. 1. In greater detail, there isillustrated the cabinet 6 including the outer cabinet structureenclosure 6 composed of plastic sheet 6a laminated to celluslosicfiberboard. Fiber glass sound-absorbing sheet 11b may be utilized aloneor as illustrated laminated or otherwise attached to and/or spaced fromtypically a cellulosic fiberboard or other substantially rigid insulatorsheet. Space 15 is defined between the inner enclosure structure 11 andthe outer enclosure structure 6. The inner enclosure structure 11 joinsthe outer enclosure structure at a point adjacent the membrane unit 7.It of course also would be possible for the membrane unit to be anchoredto both the inner enclosure structure 11 and/or the outer enclosurestructure 6.

FIG. 2 also illustrates the cone 9, the cone support 12 having openingsor apertures 13, and the electromagnet 16, as well as an in-part view ofthe electric cord 14. The electromagnet and the cone and cone supportare located within the enclosed space 17. Within the dotted linerectangle is the portion of FIG. 2 represented in enlarged view in FIG.3.

FIG. 3 in detail represents a more clear picture of the laminatedenclosure structure 6 including sheets 6a and 6b 6a and 6b and thelaminated enclosure structure 11 including 11a and 11b, as well as thecone support 12 with aperture 13 and the cone 9. More importantlyhowever is disclosed a preferred embodiment of the membrane unit 7composed of a synthetic membrane 7c such as polyester and 7a havingsandwiched between polyurethane foam 7b. It should be noted that thesheets 7a and 7c are in a taut state and that the space therebetween isin a preferred embodiment herein illustrated substantially filled by theurethane foam 7b. Also clearly illustrated is a typical mechanism ofmounting the membrane unit 7 by utilization of the annular member 8d andthe annular member 8a utilizing screws and bolts such as screw 18 andscrew 19a and bolt 19b.

Although solely polyurethane or other urethane foam has been mentioned,any suitable or desirable or conventional elastomeric material or othermedia such as already noted above may be utilized as the intermediatemedia. Additionally, other types of flexible or semiflexible supportiveplastics may be utilized as the membranes 7a and 7c of any conventionalor desirable type. Similarly, the types of plastic and/or fiberboardlaminated together may be varied as long as they are within thedescribed function thereof of having different resonances. Typicallyacrylic sheet or any other rigid or semi-rigid plastic may be utilizedpreferably in lamination with the fiberboard.

Although it is important that the speaker be suspended substantially asshown, it is within the scope and spirit of the invention that theelectromagnet and- /or cone frame support may be itself or themselvessupported in part by other nonrigid suspending media attached at otherpoints than that disclosed. Typically, polyamide sail-cloth may replacepolyester sail-cloth. The fiberboard preferably includes an outer layerof substantially firm sheet having attached to an innerface thereof asoft fiberboard sheet material of a soundabsorbing nature. Total soundabsorbing sheet material, including the above-noted soft sheet and alsothe inner enclosure preferred fiberglass sheet 11b jointly range fromabout 1 inch to about 1% inches typically one-half inch and five-eightsinch respectively. With reference to FIG. 3, as described in greaterdetail, there is disclosed the outer-frame sheet structures includingpolyester plastic first sheet 6a and cellulosic fiberboard second sheet6b, and an inner-frame sheet(s) structure including the different, fiberglass third sheet 110 mounted onto above-noted sheet 6b by theillustrated bolt, and the third sheet 11c extends substantially spacedfrom the second sheet 6b and defining the enclosure space 17, and sheet110 being laminated to and between fourth and fifth similar sheets 11aand 1111 each of cellulosic fiberboard, as particularly pointed out andclaimed in the appended claims.

I claim:

1. A loudspeaker assembly comprising in combina tion an electromagneticloudspeaker including an electromagnet and a conical vibratory coneoperatively connected to each other, the cone outer periphery abutting amembranous diaphragm means having inner and outer peripheral edges withthe abutting being at about the peripheral inner edge, the membranousdiaphragm means having an opening therein defined by said innerperipheral edge, a first enclosure structure enclosing saidelectromagnet and coneand including a speaker-mounting opening definedby first enclosure structure peripherally around said opening, saidmembranous diaphragm means outer edge being attached to and supported bysaid first enclosure speaker-openingdefining structure with saiddiaphragm means mounted in a substantially taut state, the diaphragmmeans comprising a plurality of supportive membranous sheets each havingfront and back faces, the sheets being mounted in substantially parallelplanes with one another, and an intermediate media sealed between and incontact with each of opposing ones of faces of said plurality.

2. A loudspeaker assembly of claim 1, in which said intermediate mediacomprises an elastomeric composition.

3. A loudspeaker assembly of claim 2, in which said elastomericcomposition comprises substantially polyurethane foam.

4. A loudspeaker assembly of claim 3, in which said enclosure structurecomprises laminated plastic sheet and cellulosic fiber-board sheet, andsound-absorbing insulation mounted within said enclosure and spaced fromsaid cone.

5. A loudspeaker assembly of claim 1, in which said plurality comprisestwo opposing membranes separated by said intermediate media.

6. A loudspeaker assembly of claim 5, in which said opposing membranesare each flexible polyester membranes.

7. A loudspeaker assembly of claim 1, including a second enclosurehaving open-end structure defining a second opening arranged inalignment with said first speaker structure opening, said open-endstructure of said second enclosure structure joining said peripheralouter edge and said second enclosure structure being mounted on andwithin the enclosing structure thereof spaced from the first enclosingstructure at substantially all points such that an intermediate space isdefined between the first enclosure structure and the second enclosurestructure, in which said electromagnetic loudspeaker includes anapertured frame in supporting relationship with said electromagnet withthe frame mounted on said diaphragm means inner periphery, and in whichsaid cone is substantially conical.

8. A loudspeaker assembly of claim 1, including a second enclosurehaving open-end structure defining a second opening arranged inalignment with said first speaker structure opening, said open-endstructure of said second'enclosure structure joining said peripheralouter edge and said second enclosure structure being mounted on andwithin the enclosing structure thereof spaced from the first enclosingstructure at substantially points such that an intermediate space if isdefined between the first enclosure structure and the second enclosurestructure, in which said electromagnetic loudspeaker includes anapertured frame in supporting I relationship with said electromagnetwith the frame mounted on said disphragm means inner periphery.

9. A loudspeaker cabinetlcomprising in combination a laminated enclosurestructure defining an opening receivable of and mountable therein of anelectromagnetic speaker cone and electromagnet means within an enclosurespace defined by the enclosure structre, said laminated enclosurestructure including an outer layer of a first sheet structure of firstpredetermined resonance properties having an inner face, a second layerof a second different sheet structure laminated to said inner face, saidsecond sheet structure having an inner face and having secondpredetermined resonance properties different from said first sheetstructure, a third different and substantially sound-absorbing sheetstructure mounted about adjacent an inner side of and extendingsubstantially spaced from said second sheets inner face and definingsaid enclosure space.

10. A loudspeaker cabinet of claim 9, in which said enclosing structurefurther includes a substantially sound-absorbing fourth sheet laminatedon an outer and said fourth sheet structure in a face to facerelationship.

12. The loudspeaker cabinet of claim 11, in which said first sheetstructure comprises polyester plastic sheet, in which said second sheetstructure comprises substantially hard cellulosic fiberboard sheet, inwhich said fourth and fifth sheet structures each comprise softcellulosic fiberboard sheet, and in which said third structure comprisesfiberglass.

t t t

1. A loudspeaker assembly comprising in combination an electromagneticloudspeaker including an electromagnet and a conical vibratory coneoperatively connected to each other, the cone outer periphery abutting amembranous diaphragm means having inner and outer peripheral edges withthe abutting being at about the peripheral inner edge, the membranousdiaphragm means having an opening therein defined by said innerperipheral edge, a first enclosure structure enclosing saidelectromagnet and cone and including a speaker-mounting opening definedby first enclosure structure peripherally around said opening, saidmembranous diaphragm means outer edge being attached to and supported bysaid first enclosure speaker-opening-defining structure with saiddiaphragm means mounted in a substantially taut state, the diaphragmmeans comprising a plurality of supportive membranous sheets each havingfront and back faces, the sheets being mounted in substantially parallelplanes with one another, and an intermediate media sealed between and incontact with each of opposing ones of faces of said plurality.
 2. Aloudspeaker assembly of claim 1, in which said intermediate mediacomprises an elastomeric composition.
 3. A loudspeaker assembly of claim2, in which said elastomeric composition comprises substantiallypolyurethane foam.
 4. A loudspeaker assembly of claim 3, in which saidenclosure structure comprises laminated plastic sheet and cellulosicfiber-board sheet, and sound-absorbing insulation mounted within saidenclosure and spaced from said cone.
 5. A loudspeaker assembly of claim1, in which said plurality comprises two opposing membranes separated bysaid intermediate media.
 6. A loudspeaker assembly of claim 5, in whichsaid opposing membranes are each flexible polyester membranes.
 7. Aloudspeaker assembly of claim 1, including a second enclosure havingopen-end structure defining a second opening arranged in alignment withsaid first speaker structure opening, said open-end structure of saidsecond enclosure structure joining said peripheral outer edge and saidsecond enclosure structure being mounted on and within the enclosingstructure thereof spaced from the first enclosing structure atsubstantially all points such that an intermediate space is definedbetween the first enclosure structure and the second enclosurestructure, in which said electromagnetic loudspeaker includes anapertured frame in supporting relationship with said electromagnet withthe frame mounted on said diaphragm means inner periphery, and in whichsaid cone is substantially conical.
 8. A loudspeaker assembly of claim1, including a second enclosure having open-end structure defining asecond opening arranged in alignment with said first speaker structureopening, said open-end structure of said second enclosure structurejoining said peripheral outer edge and said second enclosure structurebeing mounted on and within the enclosing structure thereof spaced fromthe first enclosing structure at substantially points such that anintermediate space is defined between the first enclosure structure andthe second enclosure structure, in which said electromagneticloudspeaker includes an apertured frame in supporting relationship withsaid electromagnet with the frame mounted on said diaphragm means innerperiphery.
 9. A loudspeaker cabinet comprising in combination alaminated enclosure structure defining an opening receivable of andmountable therein of an electromagnetic speaker cone and electromagnetmeans within an enclosure space defined by the enclosure structure, saidlaminated enclosure structure including an outer layer of a first sheetstructure of first predetermined resonance properties having an innerface, a second layer of a second different sheet structure laminated tosaid inner face, said second sheet structure having an inner face andhaving second predetermined resonance properties different from saidfirst sheet structure, a third different and substantiallysound-absorbing sheet structure mounted about adjacent an inner side ofand extending substantially spaced from said second sheet''s inner faceand defining said enclosure space.
 10. A loudspeaker cabinet of claim 9,in which said enclosing structure further includes a substantiallysound-absorbing fourth sheet laminated on an outer face of said thirdsheet circumscribing said enclosure space and spaced from said secondsheet structure and in the laminated state substantially enclosable ofsaid cone and said electromagnetic means when mounted in said cabinet upto a periphery of said opening within said space.
 11. The loudspeakercabinet of claim 10, and further including a fifth sheet structure aboutthe same as said fourth sheet structure, spaced from said second sheetstructure and with said third sheet structure located between andattached flushly to said fifth sheet structure and said fourth sheetstructure in a face to face relationship.
 12. The loudspeaker cabinet ofclaim 11, in which said first sheet structure comprises polyesterplastic sheet, in which said second sheet structure comprisessubstantially hard cellulosic fiberboard sheet, in which said fourth andfifth sheet structures each comprise soft cellulosic fiberboard sheet,and in which said third structure comprises fiberglass.